The present invention relates to foldable agricultural implements designed to be used in a towed relation to a tractor or other motive means. Particularly desirable in such devices are the abilities to be quickly folded for transport and unfolded for use in the field, and to perform work over a wide area while maintaining a uniform closely spaced relation between the ground-working means and the soil. Several devices currently available provide some of these desirable attributes, but do so at the sacrifice of the other attributes and practical necessities such as maneuverability, simplicity and stability. Typical problems include the need for long center tongues for foldability which decrease maneuverability; multiple complex hinges and universal joints for combining foldability and contour following which complicate construction and add expense; and requirements of more than four ground wheels for stability, which also adds expense.
Several currently available implements attempt to deliver these desirable attributes, but do so to a lesser degree than the present invention or do so inadequately. For instance, the ground clearance of some implements currently available is less than twelve inches, which is insufficient for travel over many rural roads and can result in damage to the implements if roadside hazards are struck, low ground clearance can also be insufficient for entrance to and exit from fields where ravines and rough terrain may be encountered. Other implements provide inadequate uniformity of proximity of the implement to the soil in the field causing erratic planting depth, which can result in crop damage and decreased yields. Lastly, the complexity of combining the desirable attributes unduly increases the cost of purchase and maintenance of those devices.